A single employee of a sandwich chain who came back to work too early after suffering from a stomach virus infected more than 100 office workers who ate party-sized submarine sandwiches last year, federal health officials reported.
The U.S. Centers for Disease Control and Prevention said the man passed a norovirus on to three separate office parties in Kent County, Mich., in May last year.
And it took a week for the restaurant to be closed and properly disinfected afterward, the CDC said in its weekly report on death and illness.
"Illnesses at a publishing company, school, social service group, and among members of the public resulted in closure of a warehouse, employee absences, pay for substitute teachers, loss of wages, and loss of revenue to the restaurant during a week-long closure," the CDC report reads.
"The three outbreaks and community cases all appeared to have been linked to sandwiches prepared by the same restaurant."
Noroviruses are the most common cause of stomach illness.
They almost always cause vomiting and diarrhea, as well as other symptoms. They are easily passed on by people who do not wash their hands properly and can cause outbreaks in restaurants, cruise ships and other large gatherings.
Three separate office parties ordered giant submarine sandwiches from the franchise, and the same worker, whose job was to wash and cut lettuce, helped prepare them all. People at all three parties were sickened, as were 25 other people who bought food at the restaurant.
All those who could be sampled were infected with genetically similar viruses, the CDC said.
It said people who have been sick with a stomach virus should not return to work until they have been well for at least a day and the new Michigan rules stipulate that sick workers stay home for 48 to 72 hours after their symptoms end.